1. Field of the Invention
The present invention relates to a dual-chamber type injector accommodating two components, an injection drug and its dissolving liquid, within, respectively, a syringe and a hermetically closed container such as a vial or the like separately from each other and to a connector used for this dual-chamber type injector. More specifically, it is directed to an injector and a connector used therefor, the injector being compact in shape but able to assuredly retain sterility while being stored and to mix both of the accommodated components surely through a simple operation just before administration. Further, the injector is unlikely to damage the sharpness of an injection needle during a mixing operation and is capable of removing the syringe simply after the mixing operation.
2. Description of the Prior Art
Some of the drugs to be administered by injection change in quality over time if dissolved in a dissolving liquid or the like. Therefore, generally a powder injection drug is stored in a dry state and mixed with and dissolved in a dissolving liquid just before administering it.
Ordinarily, the powder injection drug and its dissolving liquid are hermetically packed, for example, in, respectively, a vial and an ampul separately from each other. When they are used for administration, first an injector sucks the dissolving liquid within the ampul and pours it into the vial to dissolve the powder injection drug therein, and then sucks the dissolved drug again. However, these mixing and dissolving operations are troublesome. Besides, an injection needle pierces a vial's closure member in contact with the air, so that it is not easy to keep the injection needle and the mixed injection drug sterile.
In order to solve the above problems, there exists, for example, an injector previously proposed and disclosed in Japanese Patent Public Disclosure No. 5-31189 by the present Applicant as a dual-chamber type injector which incorporates two components and a syringe integrally thereinto so as to facilitate the mixing operation in a sterile state.
The above-mentioned conventional dual-chamber type injector, for example, as shown in FIG. 32, has a syringe 83 accommodating a first powder component 81 slidably inserted from an opening 87 provided at a rear end of an external cylinder 86 and hermetically seals a drug accommodating chamber 85 within the syringe 83 by embedding a front end of an injection needle 84 in a sealing member 88 provided at a front end of the external cylinder 86. The external cylinder 86 supports a hermetically closed container 89 which includes a container chamber 96 accommodating a second liquid component 82. A closure member 91 attached to a takeout port 90 of the container 89 is intimately contacted with the sealing member 88 and a cover 92 is attached to the opening 87 at the rear end of the external cylinder 86 so as to airtightly cover the syringe 83.
The cover 92 has a flange portion 93 formed with an annular easily-broken portion 94.
With the foregoing dual-chamber type injector 80, when an external force is applied to a rear end of the cover 92, for example, by pushing the external cylinder 86 onto a desk from above, the easily broken portion 94 breaks. If it is further pushed, a piston 95 is pressed to increase the inner pressure of the drug accommodating chamber 85 and at the same time relatively move the syringe 83 while sliding it toward the container 89. Then the front end of the injection needle 84 enters the container chamber 96 by piercing the sealing member 88 and the closure member 91, thereby allowing gas to flow from the drug accommodating chamber 85 into the container chamber 96 to result in increasing the pressure within the container chamber 96.
Next, if the foregoing pushing force is cancelled, the increased pressure within the container chamber 96 retracts the piston 95 and causes the second liquid component 82 to flow into the drug accommodating chamber 85 through the injection needle 84. The first powder component 81 is mixed with and dissolved in this flowed-in second component 82.
Subsequently, excessive gas flowed into the syringe 83 is discharged by operating the piston 95 and then the syringe 83 is extracted from the external cylinder 86 to be used for drug administration.
3. Problems Presented by the Prior Art
The conventional dual-chamber type injector has the following problems:
(1) Since the hermetically closed container is arranged ahead of the injection needle attached to the front end of the syringe through the sealing member, the injector becomes large in its entire length and is therefore bulky when stored. PA1 (2) A metal injection needle is fixed to the front end of the syringe; it is not easy to dispose of the metal injection needle separately from the other non-metallic portions after the injector is used. PA1 (3) The drug accommodating chamber is communicated with the container chamber through a slot within the injection needle. Accordingly, the drug or the like does not readily move and therefore requires much time for movement. In addition, the powder drug clogs the slot to interrupt the communication between the drug accommodating chamber and the container chamber, causing a fear of failure to assuredly mix both components. PA1 (4) When mixing both the components, the injection needle has to pierce through the sealing member and the closure member. This is likely to produce rubber dust or the like when piercing and to decrease the sharpness of the injection needle. Accordingly, the injection needle cannot easily pierce the skin of a patient and additionally may give great pain to the patient. PA1 (5) When the syringe is dismantled from the connector after the mixing operation, it is necessary to straightly extract the injection needle from the sealing member or the closure member so as not to apply an excessive external force to the injection needle, and therefore a careful operation is needed. PA1 bioactive peptide; anti-tumor agent; antibiotic; antipyretic agent; analgestic agent; anti-inflammatory agent; anti-tussive and expectorant agent; sedative; muscle relaxant; anti-epilepsy agent; anti-ulcer agent; anti-depression agent; anti-allergic agent; cardiac, arrhythmia therapeutic agent; vasodilator; antihypertensive and diuretic agent; diabetes therapeutic agent; anti-lipemia agent; anti-blood clotting agent; hemostatic; anti-tuberculosis agent; hormone agent; antinarcotic; bone resorption inhibitor; osteogenesis promoter; and blood-vessel-growth inhibitor. PA1 luteinizing hormone releasing hormone (LH-RH) and its analogues; LH-RH agonist or LH-RH antagonist; insulin; erythropoietin; somatostatin; somatostatin derivatives; growth hormone; human growth hormone; prolactin; adrenocorticotropic hormone (ACTH); ACTH derivatives (such as ebiratide), melanocyte stimulating hormone (MSH); and thyroid hormone releasing hormone [expressed in a structural formula of(Pyr)Glu-His-Pro-NH.sub.2 and sometimes abbreviated as `TRH`], its salts and derivatives. PA1 (2R,4S)-(--)-N-[4-(diethoxyphosphorylmethyl)phenyl]-1,2,4,5-tetrahydro-4-me thyl-7,8-methylenedioxy-5-oxo-3-benzothiepine-2-carboxamide, its salts and derivatives.